Astronomer Geoff Marcy specializes in searching for things that may not exist. Twenty years ago, he found the first planets outside our solar system by observing their gravitational effect on the distant stars they orbit. Now he’s turned his attention to something even more elusive — extraterrestrial intelligence.

As the head of the SETI program at the University of California at Berkeley, Marcy scans the sky for laser beams, a much more efficient medium for interstellar communication than old-fashioned radio waves. On this episode of the Storyboard podcast, he invites Wired senior editor Adam Rogers to his office to talk about why Earth might not be so special, how to define intelligence before you can look for it, and why science should occasionally swing for the fences, even if a home run is unlikely.